In a medium saucepan, heat cream and butter over medium-low heat until butter is melted. Add sugar; cook, whisking frequently, until sugar mostly dissolves, 6 to 8 minutes. Add cocoa, corn syrup, cinnamon, salt, and red pepper (if using); cook, whisking constantly, until smooth and

well combined, 2 to 3 minutes. Stir in chocolate until melted. Remove from heat. Add more cream if a thinner consistency is desired. Serve warm. Refrigerate in an airtight container for up to 1 week. (To reheat, microwave on high in 10-second intervals, stirring between each, until melted and smooth.)